I. Field of the Disclosure
The technology of the disclosure relates generally to middle-of-line (MOL) manufacturing processes for integrated circuits (ICs), and particularly to facilitating interconnections between metal lines in a metal layer.
II. Background
Computing devices have become commonplace throughout society. The increasing presence of such computing devices has accelerated in part because of the increasing functionality and versatility of such computing devices. This increase in functionality and versatility has been enabled by providing increasingly powerful processing capabilities in small packages, as loosely recognized by Moore's Law. The pressures to increase processing capabilities while decreasing the size of integrated circuits (ICs) has strained conventional manufacturing processes, especially as node size has been reduced to the low nanometer (nm) dimension (e.g., <20 nm).
Current semiconductor fabrication of ICs may include front-end-of-line (FEOL), middle-of-line (MOL), and back-end-of-line (BEOL) processes. The FEOL processes may include wafer preparation, isolation, well formation, gate patterning, spacer, extension, source/drain implantation, silicide formation, and the like. The MOL processes may include gate contact formation and interconnection between differing layers of an IC. The BEOL processes may include a series of wafer processing steps for interconnecting semiconductor devices created during the FEOL and MOL processes. Successful fabrication and qualification of modern semiconductor chip products involves an interplay between the materials and the processes employed. In particular, coupling metal lines in a metal layer in a MOL IC during the MOL processes is increasingly challenging at the current low nanometer (nm) node sizes, particularly for lithography printing. As MOL stacks are scaled down, the pitch of the metal lines is further reduced such that it may not be possible to provide interconnection vias in a layer above the metal lines for metal line interconnections due to the tight pitch.